Method for continuously recovering dimethylformamide from waste solution resulting from production of polyimide

A method for recovering dimethylformamide from a polyimide production waste solution containing dimethylformamide, acetic acid, a catalyst, and water, the method comprising:

• (a) a neutralization process of forming the acetic acid into a non-volatile acetate by adding a metal hydroxide to the waste solution;
• (b) a first distillation process of removing the water contained in the waste solution that has gone through the step (a);
• (c) a second distillation process of separating and removing the non-volatile acetate from the waste solution from which at least a portion of the water has been removed through the step (b);
• (d) a water content control process of controlling the water content in the waste solution by adding water to the waste solution to avoid the dimethylformamide and the catalyst contained in the distilled waste solution in the step (c) becoming an azeotropic mixture state;
• and
• (e) a third distillation process of separating and recovering dimethylformamide from the waste solution by performing fractional distillation on the waste solution in the step (d).